1. Department of Computer Science and Engineering, UCSC, Santa Cruz, CA, USA
2. Department of Computer Science and Information Engineering, National Chung Cheng University, Chiayi, Taiwan
3. Department of Computer Science and Information Engineering, Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, Chiayi, Taiwan
4. Research Center for Information Technology Innovation, Academia Sinica, Taipei City, Taiwan